"In recent years, there have been many studies showing that people's self-reports of energy intake and body weight are not truthful. These types of data can be verified. The studies show that people's responses are affected by what is considered to be socially desirable. That being the case, should sexuality researchers continue to assume that self-reports of sexual behavior are truthful?" said study author Bruce King, a professor of psychology at Clemson University.

"The problem is that sexuality researchers can never actually verify the truthfulness of responses," he continued. Actual penis size was not verified in this study, but "it is highly unlikely that many of the men reported truthfully and the correlation with scores on the Marlowe-Crowne Social Desirability scale indicate that many men probably exaggerated in the direction that men find to be desirable. If these self-reports cannot be trusted, why should we trust that people answer honestly on other questions regarding sexuality?"

Researchers asked 166 male college students to complete the Marlowe—Crowne Social Desirability Scale and then report the length of their penis when erect. "The Marlowe—Crowne scale assesses whether participants are responding truthfully or responding with inaccurate but socially desirable answers," writes the PsyPost report.

"The researchers found a positive correlation between social desirability scores and penis length. In other words, men more concerned with social approval tended to say they had longer penises," the report continued.

"The average person probably would not be interested in academic questions such as self-reports and correlations with social desirability. However, of secondary importance is that the often repeated statement that the average size erect penis is 6.0-6.25 inches is probably a myth, based on many studies in which men self-reported penis size," King told PsyPost.

"The grand mean for four studies in which researchers took measurements was 5.36 inches (and a fifth study with several hundred Korean military men found 4.75 inches). This has probably led many men to feel inadequate and insecure."